Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
After going through your medical details I understand your concern. first, with arterial blood pressures of 170/102mmHg your brother has uncontrolled arterial hypertension.
Second, it is important to differentiate the terms dizziness, vertigo, and syncope or pre-syncope. The drop in Blood pressure with an increase in heart rate, with "tunnel vision" suggests that it is more likely to be dizziness or syncope, rather than vertigo. Postural
orthostatic tachycardia syndrome (POTS) is a condition in which a change from lying to standing causes an abnormally large increase in heart rate. This occurs with symptoms that may include
lightheadedness, trouble thinking, blurry vision, or weakness. but studies are needed to establish the diagnosis. For this reason, I recommend consulting with your attending physician as soon as possible for a physical exam and some tests:
- a ECG
- Exclude autonomic disorders:
Thyroid Function Tests, fasting glycemia
- blood electrolytes
-
complete blood count, PCR, ESR for inflammation.
You should discuss with your doctor on the above tests.
Hope I have answered your query. Let me know if I can assist you further.